Five kinds of CA-Pro-Xaa- NH2, 11, 15, 10, 2 and 20, showed slightly higher % RSA than 7
(CA-Pro-His-NH2). However, considering the results from the DPPH radical-scavenging test and lipid peroxidation inhibition test, 7 (CA-Pro-His-NH2) was the best antioxidant.